MIPS: Fix several failures due to unsupported Sed and Seh innstructions on MIPS32R1

src/mips/macro-assembler-mips.h

Index: src/mips/macro-assembler-mips.h
diff --git a/src/mips/macro-assembler-mips.h b/src/mips/macro-assembler-mips.h
index 6c4e1ab62ac9dc8a01f51d71ee2f8fd960d59b89..9eb8d54d9b8754a35f004087a392f44bff104517 100644
--- a/src/mips/macro-assembler-mips.h
+++ b/src/mips/macro-assembler-mips.h
@@ -833,6 +833,8 @@ class MacroAssembler: public Assembler {
   // MIPS32 R2 instruction macro.
   void Ins(Register rt, Register rs, uint16_t pos, uint16_t size);
   void Ext(Register rt, Register rs, uint16_t pos, uint16_t size);
+  void Seb(Register rd, Register rt);
+  void Seh(Register rd, Register rt);
   void Neg_s(FPURegister fd, FPURegister fs);
   void Neg_d(FPURegister fd, FPURegister fs);